Field of the Invention
The present invention relates to a battery pack for an electric work vehicle propelling and performing work operation with an electric motor, and an electric work vehicle loaded with the battery pack.
Related Art of the Invention
Electric vehicles driven by rotary power from electric motors have been widespread in the automobile filed. Such an electric vehicle is loaded with a battery as a power source for the electric motor. In many cases, the battery includes a cooling system for keeping the battery temperature at a proper level to maintain the performance of the battery. An example of conventional battery packs for vehicles is disclosed in Japanese Unexamined Patent Application Publication No. 2014-075181 (JP 2014-075181 A), which corresponds to German Patent Application No. DE 10 2013 219 452 A1. The battery pack includes a casing, a plurality of battery cells housed in the casing, and a cooling fan housed in the casing for directing air to the battery cells. The casing includes an inlet for introducing air from the outside into the casing, and an outlet for discharging air to the outside of the casing. An air flow generated by rotation of the cooling fan passes through gaps defined between the battery cells, and through an intake passage extending in a bottom space defined between an inner bottom surface of the casing and a bottom surface of the battery cells. More particularly, the cooling air introduced from the outside into the casing via the inlet passes through the intake passage, the bottom space, and the gaps between the battery cells to be discharged to the outside from the outlet. The battery pack further includes a plurality of radiator fins projecting downward from the bottom surface of the casing.
On the other hand, work vehicles such as a lawn mower, a rice transplanter and a tractor, have to travel and perform work operation at a same time in ambience poorer than ambience for automobiles. Thus, cooling air, which are introduced from the ambience, easily entrains glass clippings or straws. As a result, a cooling air passage is easily choked up with such foreign matters.